TRADITIONAL METHOD ...
Step 1.) Using a marking tool designed for drawing on plastic (an Ultra Fine Point Sharpie® pen works great), carefully trace template diagram lines onto template plastic (available in most quilt shops and fabric stores).

Step 2.) Cut out plastic templates using the outer, solid line as the cutting guide. Cut directly on the inside edge of the drawn line.

Step 3.) Place plastic template on the fabric and draw around the template with a sharp "fabric" marking pen or pencil. Using scissors, cut out the fabric. NOTE: If the template diagrams have intersecting marks indicated on them, mark intersecting points (match points or registration marks) on the wrong side of the respective fabric pieces. (Diagram I) When working with reverse pieces, draw line around template, right side up, then turn the template over and repeat the line drawing step to create the reverse piece.

Diagram I

QUICK AND EASY METHOD ...
Step 1.) Using the outer solid line of the template diagram as a guide, cut out the "paper" template. (TIP: Print or copy two sets of template diagrams for each pattern requiring the use of templates. Keep one for your file and one to cut out.

Step 2.) Turn paper template over and place masking tape on the back. (Diagrams II, III, and IV)

Stick a small piece of masking tape to back of paper template.
Diagram II

Roll a second piece of tape, sticky side out. Diagram III

Place rolled tape on top of flat piece. Diagram IV

NOTE: Placing a rolled piece of tape on top of another piece of tape allows for easy removal of the rolled piece, without tearing the paper template. (When cutting reverse pieces, fold fabric wrong side to wrong side or right side to right side, depending on the pattern, and cut both pieces together.)

Step 3.) Place fabric on rotary cutting mat, right side up. Aligning arrow on template with straight grain of fabric, lay paper template on fabric (rolled tape down). Press down on the taped area to temporarily adhere template to fabric.

Step 4.) Place ruler's ¼" line on top of template's seam allowance line (broken line) on the side being cut. Begin and end cutting approximately ¼" away from edge of template. (Diagram V)

Step 5.) Turn fabric, or mat, (tape will prevent the template from slipping out of place) and cut the next side. (Diagram VI) Continue turning and cutting until all sides have been cut. Carefully remove template/tape from fabric.

Diagram V

Diagram VI